Filter Columns in a QFileSystemModel: Difference between revisions

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[[Category:HowTo]]<br />[[Category:snippets]]
[[Category:HowTo]]
[[Category:snippets]]


= How to Filter Columns in a QFileSystemModel =
= How to Filter Columns in a QFileSystemModel =


Sometimes one does not want to display all the columns of a &quot;QFileSystemModel&amp;quot;:http://doc.qt.nokia.com/stable/qfilesystemmodel.html, like discussed in &quot;this forum thread&amp;quot;:http://developer.qt.nokia.com/forums/viewthread/3114/.
Sometimes one does not want to display all the columns of a "QFileSystemModel":http://doc.qt.nokia.com/stable/qfilesystemmodel.html, like discussed in "this forum thread":http://developer.qt.nokia.com/forums/viewthread/3114/.


This can be achieved in two ways, either by hiding the columns in the view, by using a specialized proxy model. The easiest way is to hide the columns using the &lt;code&amp;gt;QHeaderView&amp;lt;/code&amp;gt;, but the alternative to subclass &quot;QSortFilterProxyModel&amp;quot;:http://doc.qt.nokia.com/stable/qsortfilterproxymodel.html and reimplement the &lt;code&amp;gt;filterAcceptsColumn()&lt;/code&amp;gt; method also works well.
This can be achieved in two ways, either by hiding the columns in the view, by using a specialized proxy model. The easiest way is to hide the columns using the <code>QHeaderView</code>, but the alternative to subclass "QSortFilterProxyModel":http://doc.qt.nokia.com/stable/qsortfilterproxymodel.html and reimplement the <code>filterAcceptsColumn()</code> method also works well.


== Column hiding using QHeaderView ==
== Column hiding using QHeaderView ==


All multi-column views provide access to a &quot;QHeaderView&amp;quot;:http://doc.qt.nokia.com/stable/qheaderview.html . This is the widget that provides the headers above the columns of data, and allows the user to resize those columns, or click the headers to trigger a sorting order. You can also use this widget to hide columns in your view.
All multi-column views provide access to a "QHeaderView":http://doc.qt.nokia.com/stable/qheaderview.html . This is the widget that provides the headers above the columns of data, and allows the user to resize those columns, or click the headers to trigger a sorting order. You can also use this widget to hide columns in your view.


<code><br />//hide the third and fourth column, note that the column numbers are 0-based<br />QHeaderView* hHeader = m_theTableview-&gt;horizontalHeader();<br />hHeader-&gt;hideSection(2);<br />hHeader-&gt;hideSection(3);<br /></code>
<code>
//hide the third and fourth column, note that the column numbers are 0-based
QHeaderView* hHeader = m_theTableview->horizontalHeader();
hHeader->hideSection(2);
hHeader->hideSection(3);
</code>


The alternative method of using a custom proxy model is outlined below.
The alternative method of using a custom proxy model is outlined below.
Line 19: Line 25:
Be aware that the column count is 0-based and that it is hard coded.
Be aware that the column count is 0-based and that it is hard coded.


==== fsmproxy.h<br /><code><br />#include &lt;QSortFilterProxyModel&amp;gt; ====
==== fsmproxy.h
<code>
#include <QSortFilterProxyModel> ====


class FSMProxy : public QSortFilterProxyModel<br />{<br /> Q_OBJECT
class FSMProxy : public QSortFilterProxyModel
{
Q_OBJECT


public:<br /> FSMProxy(QObject *parent);
public:
FSMProxy(QObject *parent);


protected:<br /> bool filterAcceptsColumn(int source_column, const QModelIndex &amp;source_parent) const;<br />};<br /></code>
protected:
bool filterAcceptsColumn(int source_column, const QModelIndex &amp;source_parent) const;
};
</code>


==== fsmproxy.cpp<br /><code><br />FSMProxy::FSMProxy(QObject *parent)<br /> : QSortFilterProxyModel(parent)<br />{<br />} ====
==== fsmproxy.cpp
<code>
FSMProxy::FSMProxy(QObject *parent)
: QSortFilterProxyModel(parent)
{
} ====


bool FSMProxy::filterAcceptsColumn(int source_column, const QModelIndex &amp;source_parent) const<br />{<br /> Q_UNUSED(source_parent)
bool FSMProxy::filterAcceptsColumn(int source_column, const QModelIndex &amp;source_parent) const
{
Q_UNUSED(source_parent)


    // adjust the columns you want to filter out here<br />    // return false for those that will be hidden<br /> if(source_column  2 || source_column  3)<br /> return false;<br /> return true;<br />}<br /></code>
    // adjust the columns you want to filter out here
    // return false for those that will be hidden
if(source_column  2 || source_column  3)
return false;
return true;
}
</code>


==== Usage<br /><code><br />    QFileSystemModel *fsm = new QFileSystemModel(this);<br />    FSMProxy *proxy = new FSMProxy(this);<br />    proxy-&gt;setSourceModel(fsm);<br />    treeView-&gt;setModel(proxy);<br /></code> ====
==== Usage
<code>
    QFileSystemModel *fsm = new QFileSystemModel(this);
    FSMProxy *proxy = new FSMProxy(this);
    proxy->setSourceModel(fsm);
    treeView->setModel(proxy);
</code> ====

Revision as of 10:14, 25 February 2015


How to Filter Columns in a QFileSystemModel

Sometimes one does not want to display all the columns of a "QFileSystemModel":http://doc.qt.nokia.com/stable/qfilesystemmodel.html, like discussed in "this forum thread":http://developer.qt.nokia.com/forums/viewthread/3114/.

This can be achieved in two ways, either by hiding the columns in the view, by using a specialized proxy model. The easiest way is to hide the columns using the

QHeaderView

, but the alternative to subclass "QSortFilterProxyModel":http://doc.qt.nokia.com/stable/qsortfilterproxymodel.html and reimplement the

filterAcceptsColumn()

method also works well.

Column hiding using QHeaderView

All multi-column views provide access to a "QHeaderView":http://doc.qt.nokia.com/stable/qheaderview.html . This is the widget that provides the headers above the columns of data, and allows the user to resize those columns, or click the headers to trigger a sorting order. You can also use this widget to hide columns in your view.

//hide the third and fourth column, note that the column numbers are 0-based
QHeaderView* hHeader = m_theTableview->horizontalHeader();
hHeader->hideSection(2);
hHeader->hideSection(3);

The alternative method of using a custom proxy model is outlined below.

Column hiding using QSortFilterProxyModel

Be aware that the column count is 0-based and that it is hard coded.

==== fsmproxy.h

#include <QSortFilterProxyModel> ====

class FSMProxy : public QSortFilterProxyModel
{
 Q_OBJECT

public:
 FSMProxy(QObject *parent);

protected:
 bool filterAcceptsColumn(int source_column, const QModelIndex &amp;source_parent) const;
};

==== fsmproxy.cpp

FSMProxy::FSMProxy(QObject *parent)
 : QSortFilterProxyModel(parent)
{
} ====

bool FSMProxy::filterAcceptsColumn(int source_column, const QModelIndex &amp;source_parent) const
{
 Q_UNUSED(source_parent)

    // adjust the columns you want to filter out here
    // return false for those that will be hidden
 if(source_column  2 || source_column  3)
 return false;
 return true;
}

==== Usage

    QFileSystemModel *fsm = new QFileSystemModel(this);
    FSMProxy *proxy = new FSMProxy(this);
    proxy->setSourceModel(fsm);
    treeView->setModel(proxy);

====